Modern day devices helping crash investigators

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More Data Infuses NTSB’s Proven Approach

Bill Carey
Data is power in accident investigations, and the NTSB is seeing more data stored by various devices as it tracks down the root causes of aviation mishaps.

What is new in accident investigations? “The proliferation of data we get from things that are not flight data recorders,” answers John DeLisi, director of the NTSB’s Office of Aviation Safety. “It used to be that there would be a flight data recorder and cockpit voice recorder and they were crash-hardened, and when an airplane was involved in an accident that was our only source of data.

“Now, even in [general aviation] accidents, there is typically, on average, a half-dozen different things in the airplane when it crashes that can record data,” says DeLisi, who joined the NTSB in 1992 after working as a flight-test engineer for McDonnell Douglas. “There’s your cellphone, the iPad, the GPS system—all of those provide us with data. Our folks in the lab have gotten really good at extracting data from things that are not crash-hardened flight data recorders.”

Latest devices store information
Last year, the NTSB analyzed 432 recording devices
Many general aviation pilots install GoPro or other cameras in their aircraft, which can be instrumental in accident investigations. DeLisi cites the crash of a P-51D Mustang two-seat training variant in Galveston Bay, Texas, on Oct. 23, 2013, by way of example. The pilot and a passenger were killed.

The vintage aircraft had been fitted with a video and audio recording system of two cameras, one mounted in the vertical stabilizer and a second in the cockpit. Investigators recovered a video file from an SD card that provided a vivid record of the flight’s final moments. The pilot had given control of the P-51 to the passenger, and he lost situational awareness as the plane descended toward the water.

“Six months later, when a salvage company pulls [the video recording unit] up, we take it to our lab and literally just had to hit ‘play,’ and the data was all still there, all the video with audio of the accident flight,” recalls DeLisi.

Office of Research and Engineering Director James Ritter says the NTSB can extract data directly from memory cards used in devices such as iPhones, iPads, GPS units and engine-monitoring instruments; reinstall cards in surrogate devices if the host device is damaged ; and repair integrated circuits to a certain extent.

Last year, the agency analyzed 432 recording devices across different transportation modes, about 10% of which came from foreign accident investigations. These included: 82 GoPro cameras or other image recorders; 49 personal electronic devices such as mobile phones and tablet computers; 45 flight data recorders; 29 locomotive event data recorders; 26 cockpit voice recorders; and 4 marine voyage data recorders. It categorized the balance of 197 as “other” devices, such as engine monitors, glass cockpit displays and handheld GPS units.

For some 15 years, the NTSB has used an event recorder readout and graphing software tool called CIDER (for Crash Investigation Data Extraction and Readout), developed in-house, Ritter says. On the resulting data graph, engineers overlay cockpit voice recorder audio retrieved from an accident aircraft to establish a time line of what the pilots were saying and what the aircraft was doing at any given moment. This year, the agency expects to receive the first version of software developed by the Air Force Research Laboratory and other federal entities that enables synchronization of audio and video files.

Ritter also cites the utility of cameras in accident investigations. If there is a camera in the cockpit that provides a view of the instrument panel, the NTSB has software that can extract a history of the needle position on a given instrument. “We can digitize the location of the needle and calculate, say, altitude versus time just based on needle position,” he says. “You can actually derive flight-data recorder-type parametric data from cockpit video. We’ve had that capability for 10 years.”

The NTSB generates as well as recovers data—for two years it has used small drones in support of investigations. “We have deployed that technology at accident sites and it is really a game changer for us,” says DeLisi. “If an accident is in the mountains, if the debris is scattered over a long path, we’ve now got the capability of deploying our own drones to do aerial photography not only for aviation accidents but in all of the other modes.”